Answer:
[tex]\boxed {\boxed {\sf 40 \pi \ cm, 125.6 \ cm, or \ 125.6637061 \ cm}}[/tex]
Step-by-step explanation:
Circumference can be found by multiplying the diameter of the circle by pi.
[tex]c= \pi d[/tex]
We are given the radius, which is 20 centimeters. We need the diameter, which is twice the radius.
[tex]d= 2r[/tex]
[tex]d= 2(20 \ cm)[/tex]
[tex]d= 40 \ cm[/tex]
Substitute the diameter into the formula. There are many ways to calculate circumference, so I included a few options.
1. In Terms of Pi
If we solve in terms of pi, we leave π in the answer.
[tex]c=\pi ( 40 \ cm)[/tex]
[tex]c= 40 \pi \ cm[/tex]
2. Using 3.14 as Pi
[tex]c=\pi ( 40 \ cm)[/tex]
Substitute 3.14 in for pi.
[tex]c= (3.14)(40 \ cm)[/tex]
[tex]c=125.6 \ cm[/tex]
3. Using 3.14159 as PI
[tex]c=\pi ( 40 \ cm)[/tex]
Use the pi button on a calculator.
[tex]c= 125.6637061 \ cm[/tex]
The circumference of the light fixture is 40π, 125.6 cm, or 125.6637061 cm
